What is the difference between Hub and switch

Over simplified explanation :

Hubs are real dumb and switches are slightly smarter and can lower the LAN traffic in certain cases by being selective in replicating the data.

Hubs are pretty much on the way out these days and switches are almost as cheap.

For the usual home user there is no real difference. Put a half dozen users on that LAN and the switch will increase throughput.

switch: each port does not see other port's packets.

hub: each port's packets are seen on all ports and packets on one port can collide with other ports, causing more retransmission.

They do have some latency, due to reclocking the signal. However, it's very small compared to switches.

The best answer.

To add to it...

An Ethernet Switch (E-switch) breaks up each port into separate Collision Domains while hubs have just one collision domain and are basically multi-ported repeaters. E-switches on the other hand allow a node connected to a switched port to work in Full-Duplex mode and turns off the collision detection is the Ethernet standard Carrier Sense with Multiple Access (CSMA) with Collision Detection (CD). Thus a node connected to an E-switched port can send and receive at the same time. Thus a 100Mb/s NIC can have an maximum transfer rate of

200Mb/s. Since each port has its own collision domain, there are less retransmissions of sent packets, the overall effectiveness of the LAN is increased. However, on most SOHO Routers or on many cheap E-switches, the latency of the switch can offset that effectiveness. Hubs just re-time and send the signal and don't introduce a delay factor otherwise known as latency. E-switches on the other hand do introduce latency. A good switch might be rated at less than 10ns a cheap switch might be rated at 40~100ns. While that might not seem much, that is for each packet sent/received and if your sending thousands of packets it adds up.

Like a hub, there is a cross-over (X-MDI) or not crossed-over (MDI) port or a physical switch to change the state of a port from MDI to X-MDI. This uplink port allows the E-switch to be chained with others.

Physically both hubs and switches look the same but an E-switch is definitely better !

Thanx for that correction.